Sigillaria is
the generic name assigned to this ancient arborescent lycopod. It had leaves
and roots very similar to its contemporaneous cousin, lepidodendron,
but it differed in that it exhibited much rarer branching and its tall,
columnar trunk lacked the scale-pattern of lepidodendron, instead exhibiting
straight, fluted furrows along the trunk midsection. Occassionally the trunks
were smooth.

Other differences with lepidodendron were its cones. Lepidodendron cones
were attached individually near the tip of it's branches. Sigillaria cones
occurred in clusters attached in certain places along the upper stem.

Another characteristic of sigillaria are the vertically-arranged circular
scar pattern found in fossil specimens representing the inner bark. These
scars called parichnos occur in specimens assigned
the form-genus name of Syringodendron.